Plotting Earthquake Focus

Pure Geophysics Seismology

import plotly.graph_objs as go
from plotly.offline import plot, iplot, init_notebook_mode
import plotly.express as px

init_notebook_mode (connected = True)
import numpy as np
import pandas as pd

1. Import Earthquake data

Create a dataset which contains longitude, latitude, depth, and magnitude of each event. The study area of this practice is New Zealand.

df = pd.read_excel('data/meca_all.xlsx')
df.head()

	Longitude	Latitude	Depth(km)	Unnamed: 3	Unnamed: 4	Unnamed: 5	Unnamed: 6	Unnamed: 7	Unnamed: 8	Unnamed: 9	Unnamed: 10	Unnamed: 11	Unnamed: 12	Unnamed: 13	Mag	Unnamed: 15	Unnamed: 16	Unnamed: 17	Lat
0	182.31	-30.00	-44	6.98	-0.13	-6.84	1.35	2.57	-4.01	23	X	Y	090384A	7.500000e+23	5.2	NaN	-177.69	44	-30
1	183.30	-30.00	-14	1.27	-0.05	-1.22	0.33	1.28	-0.38	25	X	Y	200810050912A	1.800000e+25	6.1	NaN	-176.70	14	-30
2	183.19	-30.01	-22	1.05	0.09	-1.13	-0.21	0.01	-0.54	24	X	Y	052081B	1.100000e+24	5.3	NaN	-176.81	22	-30
3	182.84	-30.01	-17	0.95	-0.13	-0.82	-0.06	1.22	-0.35	24	X	Y	051304F	1.600000e+24	5.4	NaN	-177.16	17	-30
4	183.57	-30.01	-35	1.92	-0.16	-1.76	-0.32	-0.12	0.19	24	X	Y	200603311543A	2.000000e+24	5.5	NaN	-176.43	35	-30

2. Create a 3D plot of focus

Hover to see the details of each event. Zoom in and rotate the diagram to suit yourself.

table = df.loc[:,['Longitude','Latitude','Depth(km)','Mag']]
plot_scatter = go.Scatter3d(
    x = table['Longitude'],
    y = table['Latitude'],
    z = table['Depth(km)'],
    mode = 'markers',
    marker = dict(
        size = 5,
        cmax = 8,
        cmin = 4.5,
        color = table['Mag'],
        colorbar = dict(title = 'Magnitude'),
        colorscale = 'matter'
    )
    #title = 'Earthquake focal mechanism data from 1976 to 2020',
    #labels = {'Longitude': 'Longitude'},
    #labels = {'Latitude': 'Latitude'},
    #labels = {'Depth(km)': 'Depth(km)'},
)

plotdata = [plot_scatter]
layout = go.Layout(
    margin = dict(
        l = 0,
        r = 0,
        b = 0,
        t = 0,
    )
)
fig = go.Figure()
fig.update_layout(scene = dict(
    xaxis_title='Longitude',
    yaxis_title='Latitude',
    zaxis_title='Depth'),
    width=700,
    margin=dict(r=0, b=0, l=0, t=0))


fig = go.Figure(data = plotdata, layout = layout)
iplot(fig, filename = 'meca3D')

import pandas as pd  # (version 1.0.0)
import plotly.express as px  # (version 4.7.0)
import plotly.io as pio
import numpy as np
import plotly.graph_objects as go

Latitude-migrated 3D focus plot

You could see the subducting plate changes dip direction from westward to eastward down the latitude.

import plotly.express as px
df = pd.read_excel('data/meca_all.xlsx')
px.scatter_3d(df, x="Longitude", y="Latitude", z="Depth(km)", animation_frame="Lat", 
           size="Mag", color="Mag", size_max=15, range_x=[160,184], range_y=[-50,-30], range_z=[-600,0])

3. Create a Latitude-migrated focus cross section plot

You could see the subducting plate changes dip direction from westward to eastward down the latitude.

import plotly.express as px
df = pd.read_excel('data/meca_all.xlsx')
px.scatter(df, x="Longitude", y="Depth(km)", animation_frame="Lat", 
           size="Mag", color="Mag", size_max=10, range_x=[160,184], range_y=[-600,0])